1. Field of the Invention
The present invention relates to the use of micron-scale labels for use primarily in monitoring DNA hybridization, antibody-based immunoassays, and cellular functioning.
More particularly, the present invention relates to micron-scale shapes and reflectors, particularly retroreflectors, with highly detectable and information-rich optical properties. This invention also relates to a class of micron-scale labels made of inorganic materials, capable of high information content, and not subject to photobleaching. One class of such labels offers extremely high detectability. Primary uses for these labels are envisioned to be in DNA probe, DNA array assays, and immunoassays.
2. Description of the Related Art
Retroreflectors are widely used in road and safety signs, as misalignment-tolerant optical components, and in retroreflective paints, e.g., for lane markers. Retroreflectors are commonly used in the form of sheets of retroreflective film bearing cubical or spherical retroreflectors, arrays of large (centimeter-scale) reflectors for object detection and ranging, and spherical elements with reflective backing for safety and road markings. The background art does not provide for the use of micron-scale retroreflectors, singly or in arrays, with or without self-assembly, associated with biological recognition elements, in bioassays and biosensors.
The essential components of a bioassay are a molecular recognition element, and a label used to determine whether the recognition element is bound to a target.
Labels in current use include fluors, colored particles, and enzymes used with chromogenic, fluorogenic or chemiluminescent substrates. These suffer from a variety of drawbacks, including photobleaching, high cost, poor storage stability, competing activities in biological samples (enzymes and indigenous fluors), mutual quenching, limited detectability, and limited multiplex-ability.
Thus, there is a need in the art for stable, highly-detectable labels for bioassays and biosensors having enhanced information content and capable of self-assembling to provide low-labor assays and biosensors.